I think you are right, it's a group 4 Murena - they were N/A with very hot cams. I just re-watched the video and it stikes me that it's new - notice the Feu-Vert posters: I doubt if that business existed in the 80's and if they did, I'm sure they didn't have the same logo as they have today. This must be one of the actual cars that Politecnic used to run - wonderful!